This project includes three studies: 1) the Shanghai Biliary Tract Cancer Study, 2) The International Biliary Tract Cancer Consortium, and 3) the Chile Gallbladder Cancer Study. These studies complement each other and will provide unique insight into the etiology of biliary tract cancer. The Shanghai Study includes more than 3,000 subjects, including over 600 biliary tract cancer patients, 900 gallstone patients, and 1,000 healthy controls randomly selected from the population. A structured questionnaire was used to elicit information on epidemiologic risk factors, including smoking, drinking, diet, medical history, and reproductive factors. The study had a strong biochemical and molecular component with an extensive collection of biological samples, including serum, DNA, gallstones, bile, and tissue samples. The International Consortium Study includes 20 studies from 12 countries to pool data and samples together for a sufficiently powered study to examine the etiology of biliary tract cancer. The priority of the consortium is to conduct a GWAS to determine the role of genetic susceptibility in biliary tract cancer. The Chile Gallbladder Cancer Study includes a pilot study of 100 subjects. The full-scale study will include 4000 cases of gallbladder cancer and 4000 controls enrolled from 10 locations in Chile.